From: Jason Wang <jasowang@redhat.com> To: mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jason Wang <jasowang@redhat.com> Subject: [PATCH V2 5/6] vhost_net: poll vhost queue after marking DMA is done Date: Fri, 30 Aug 2013 12:29:21 +0800 [thread overview] Message-ID: <1377836962-49780-6-git-send-email-jasowang@redhat.com> (raw) In-Reply-To: <1377836962-49780-1-git-send-email-jasowang@redhat.com> We used to poll vhost queue before making DMA is done, this is racy if vhost thread were waked up before marking DMA is done which can result the signal to be missed. Fix this by always poll the vhost thread before DMA is done. Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/vhost/net.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index ff60c2a..d09c17c 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -308,6 +308,11 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) struct vhost_virtqueue *vq = ubufs->vq; int cnt = atomic_read(&ubufs->kref.refcount); + /* set len to mark this desc buffers done DMA */ + vq->heads[ubuf->desc].len = success ? + VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; + vhost_net_ubuf_put(ubufs); + /* * Trigger polling thread if guest stopped submitting new buffers: * in this case, the refcount after decrement will eventually reach 1 @@ -318,10 +323,6 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) */ if (cnt <= 2 || !(cnt % 16)) vhost_poll_queue(&vq->poll); - /* set len to mark this desc buffers done DMA */ - vq->heads[ubuf->desc].len = success ? - VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; - vhost_net_ubuf_put(ubufs); } /* Expects to be always run from workqueue - which acts as -- 1.7.1
WARNING: multiple messages have this Message-ID (diff)
From: Jason Wang <jasowang@redhat.com> To: mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH V2 5/6] vhost_net: poll vhost queue after marking DMA is done Date: Fri, 30 Aug 2013 12:29:21 +0800 [thread overview] Message-ID: <1377836962-49780-6-git-send-email-jasowang@redhat.com> (raw) In-Reply-To: <1377836962-49780-1-git-send-email-jasowang@redhat.com> We used to poll vhost queue before making DMA is done, this is racy if vhost thread were waked up before marking DMA is done which can result the signal to be missed. Fix this by always poll the vhost thread before DMA is done. Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/vhost/net.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index ff60c2a..d09c17c 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -308,6 +308,11 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) struct vhost_virtqueue *vq = ubufs->vq; int cnt = atomic_read(&ubufs->kref.refcount); + /* set len to mark this desc buffers done DMA */ + vq->heads[ubuf->desc].len = success ? + VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; + vhost_net_ubuf_put(ubufs); + /* * Trigger polling thread if guest stopped submitting new buffers: * in this case, the refcount after decrement will eventually reach 1 @@ -318,10 +323,6 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) */ if (cnt <= 2 || !(cnt % 16)) vhost_poll_queue(&vq->poll); - /* set len to mark this desc buffers done DMA */ - vq->heads[ubuf->desc].len = success ? - VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; - vhost_net_ubuf_put(ubufs); } /* Expects to be always run from workqueue - which acts as -- 1.7.1
next prev parent reply other threads:[~2013-08-30 4:41 UTC|newest] Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-08-30 4:29 [PATCH V2 0/6] vhost code cleanup and minor enhancement Jason Wang 2013-08-30 4:29 ` Jason Wang 2013-08-30 4:29 ` [PATCH V2 1/6] vhost_net: make vhost_zerocopy_signal_used() returns void Jason Wang 2013-08-30 4:29 ` Jason Wang 2013-09-02 5:51 ` Michael S. Tsirkin 2013-09-02 5:51 ` Michael S. Tsirkin 2013-09-02 6:29 ` Jason Wang 2013-09-02 6:29 ` Jason Wang 2013-08-30 4:29 ` [PATCH V2 2/6] vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal_used() Jason Wang 2013-08-30 4:29 ` Jason Wang 2013-09-02 5:50 ` Michael S. Tsirkin 2013-09-02 5:50 ` Michael S. Tsirkin 2013-09-02 6:28 ` Jason Wang 2013-09-02 6:28 ` Jason Wang 2013-08-30 4:29 ` [PATCH V2 3/6] vhost: switch to use vhost_add_used_n() Jason Wang 2013-08-30 4:29 ` Jason Wang 2013-08-30 4:29 ` [PATCH V2 4/6] vhost_net: determine whether or not to use zerocopy at one time Jason Wang 2013-08-30 4:29 ` Jason Wang 2013-08-30 18:35 ` Sergei Shtylyov 2013-08-30 18:35 ` Sergei Shtylyov 2013-09-02 3:15 ` Jason Wang 2013-09-02 3:15 ` Jason Wang 2013-08-30 4:29 ` Jason Wang [this message] 2013-08-30 4:29 ` [PATCH V2 5/6] vhost_net: poll vhost queue after marking DMA is done Jason Wang 2013-08-30 16:44 ` Ben Hutchings 2013-08-30 16:44 ` Ben Hutchings 2013-09-02 3:06 ` Jason Wang 2013-09-02 3:06 ` Jason Wang 2014-02-12 7:38 ` Qin Chuanyu 2014-02-12 7:38 ` Qin Chuanyu 2014-02-12 10:06 ` Jason Wang 2014-02-12 10:06 ` Jason Wang 2014-02-12 16:01 ` Michael S. Tsirkin 2014-02-12 16:01 ` Michael S. Tsirkin 2013-08-30 4:29 ` [PATCH V2 6/6] vhost_net: correctly limit the max pending buffers Jason Wang 2013-08-30 4:29 ` Jason Wang 2013-09-02 5:56 ` Michael S. Tsirkin 2013-09-02 5:56 ` Michael S. Tsirkin 2013-09-02 6:30 ` Jason Wang 2013-09-02 6:30 ` Jason Wang 2013-09-02 8:37 ` Jason Wang
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